The present invention relates to a system and method of a DVD player for displaying multiple subtitles, especially to a system and method having an accumulator register for temporarily retaining control signal of a first subtitle set image, a comparison platform for comparing a second subtitle set image control signal with the first subtitle set image control signal inside the accumulator register, and a decoder platform for decoding control signal of the subtitle image set inexistent in the accumulator register. Therefore the repeated decoding procedure of images and subtitles as well as the waste of system resources and users' time is avoided.
In earlier days, analogue storage media such as video tapes, LD (Laser Disk), V8, Hi8 will have abrasion of magnetic tape, unclear images, and difficulties in editing after being read repeatedly for a period of time. In order to improve above shortcomings, a new generation device based on VCD (video compact disk) and DVD (digital video disk) techniques is produced by the development of digital video and audio products.
In order to convert analogue video/audio information into digital data, the problem of sampling resolution and sampling rate must be solved. For reducing size of digital video/audio files, MPEG (Motion pictures experts group) technique is used widely. Although MPEG is a kind of lossy compression, it offers high compression ratio and low image distortion. As to digital video/audio products, VCD and DVD are well known and popular. However, due to the low image quality of VCD, DVD technique with better image quality has gradually received much attention.
As mentioned in U.S. Pat. No. 5,978,916, DVD is a specification for the content of video, audio and other compressed data to be used as playback video, audio and, for example, subtitle data by a DVD decoder. The DVD video data is specified in the moving picture experts group (MPEG) standard.
Moreover, refer to U.S. Pat. No. 5,907,658, with large storage capacity of DVD, it is possible for users to choose a single subtitle from subtitles of several different languages. The DVD system can replace the displaying subtitle with another subtitle of different language.
However, DVD has a disadvantage that at least two subtitles with different languages can't be displayed at the same time point. Refer to FIG. 1, a prior art of DVD technique is disclosed. A DVD player read digital data inside an optical disk 1′ and load it into a management unit 2′. Then by an identifying code of data flow, an analytic unit 3′ analyzes the digital data into a video image data flow, a subtitle image data flow and an audio data flow. And the data flows are converted into a video signal 5′, a subtitle image signal 6′, and an audio signal 7′ by a decoder unit 4′. An output unit 8′ transmits the video/audio signals into a display device for playing. Thus a prior art can only display a subtitle image. Users in receiving end can't enjoy the playing of subtitles of multi-languages.
Another common technique in a prior art, refer to Taiwanese Patent Application No. 89110234—“DVD player displaying two subtitles at the same time and the method thereof”, a receiving end can choose two subtitles before decoding procedure. Although two subtitles are displayed at the same time by this way, users in receiving end need to wait for a longer time for decoding two subtitles and images. Moreover, when users in receiving end want to re-choose two subtitles, device need to re-choose the images and two subtitles for decoding. Thus the images and subtitles are repeatedly decoded, causing waste of system resources and time.
Therefore, there is a need to provide a system and method of DVD player for displaying multiple subtitles for users.